How to Replace a Faucet Aerator: A 5-Minute Fix Most Homeowners Skip

Most aerators unscrew by hand if you grip firmly and turn counterclockwise (looking up at the bottom of the spout). The threads are usually small and shallow, so a confident wrist turn handles it.

If hand removal fails, wrap a strip of cloth, a rubber band, or a paper towel around the aerator (protects the finish from scratches), then grip with slip-joint pliers and turn counterclockwise. Apply steady pressure rather than sudden force. You’ll often feel a small “pop” as mineral deposits break free of the threads — that’s normal; keep turning by hand from there.

If it’s truly seized by mineral fusing, work up this ladder rather than forcing it: (1) wrap a vinegar-soaked cloth around the aerator for about 30 minutes to dissolve the scale on the threads; (2) warm the aerator briefly with a hair dryer on high — the metal expands and breaks the mineral bond — never use an open flame, which damages internal seals and finishes; (3) apply a little penetrating oil, wait, then rinse the threads thoroughly afterward since this is a potable-water fitting; (4) for grip without scratches, a rubber strap wrench or even a rubber jar-opener beats pliers, and a wrap of blue painter’s tape on plier jaws protects the finish. Patience here saves you from snapping the aerator off inside the spout.

For tamper-resistant or concealed (cache) aerators — common on Moen kitchen faucets and most newer designer fixtures — you’ll need the manufacturer’s specific key tool. Some Moen models use an oval hidden aerator with a 1/8” hex set-screw; newer “no visible screw” Moen designs require gently prying off the spout throat and using a 7/64” hex wrench; press-fit Moen variants (two retaining fins) require needle-nose pliers to pull straight out. Universal aerator key kits run $10–$15 (Danco’s multi-size kit is around $14). Brand-specific keys from Delta, Moen, or Kohler typically run $5–$15; specialty tools like Delta’s cache wrench are closer to $20. Two things trip people up on cache aerators: when you key one out from underneath the spout you’re looking at it upside down, so “lefty-loosey” feels reversed — go slow and watch which way it actually backs out. And on reinstall, a Neoperl-style cache aerator should be screwed in only until it sits flush, not cranked fully home — over-seating it damages the housing.

Once the aerator is off, it usually has 3–4 stacked pieces inside the outer housing:

• The outer threaded shell — what you just unscrewed
• A rubber gasket / O-ring — sits at the top, seals against the spout
• The flow restrictor — a flat washer with a calibrated hole, often colored
• The mesh screen — usually two stacked layers

Lay them out in order so you can put them back the same way. Take a photo with your phone before you separate anything — easiest reassembly guide.

Now you can see the problem. Mineral deposits look like white or brown crusty buildup on the screen and around the flow restrictor. Sometimes you’ll find pieces of rubber pipe-tape, sand, or pipe shavings — debris that worked its way through the supply line.

The decision tree on how to replace a faucet aerator vs. just clean the existing one is straightforward:

Clean if: the parts are intact (no cracks, no obvious wear) and the gunk is just mineral or sediment buildup that you can dissolve. (Don’t proceed with how to replace a faucet aerator if a simple soak gets it working — saves the $2–$10.) Drop the disassembled metal/plastic parts in a small bowl of equal-parts white vinegar and water — 5–15 minutes for light buildup, 30–60 minutes for moderate scale, 1+ hour for heavy fused deposits. After soaking, rinse and gently scrub with an old toothbrush, then reassemble.

Important — don’t apply vinegar directly to the faucet finish. Pfister and other manufacturers explicitly warn against acidic or abrasive cleaners on polished chrome, brushed nickel, or PVD-coated finishes — they can dull or pit the coating. Detach the aerator first, soak the parts in a separate container, and clean the spout itself with mild soapy water only.

Replace if: the rubber gasket is hardened or cracked, the mesh has tears, you can’t get the parts clean, or the aerator is older than 5–10 years. A replacement aerator costs $2–$8 at any hardware store. Take your old aerator with you to match the size and thread direction.

Knowing how to replace a faucet aerator is one skill; knowing which size to buy is another. Aerators come in a few standard sizes — measure the outside diameter of your old one (or compare to a coin):

• Regular (15/16″ male thread / 55/64″ female thread, ~25mm OD) — the most common kitchen and bathroom faucet size
• Junior (13/16″ male / 3/4″ female, ~22mm) — common on bar sinks and some bathroom faucets
• Tom Thumb (M18×1 male / M16×1 female, ~19mm) — small-diameter spouts and some European-style faucets

No calipers? Use a coin for a rough read: a regular aerator face is roughly quarter-sized, a junior is about nickel-sized, and a tiny Tom Thumb is around dime-sized. That gets you to the right family; confirm the exact thread against the fractions above before you buy.

Male vs. female: if your aerator threads onto the OUTSIDE of the spout (the spout has external threads), you need a male-threaded aerator. If it threads INSIDE the spout (the spout has internal threads), you need a female-threaded aerator. The quick rule when measuring: on a female aerator measure its inside diameter (it slips over the spout’s external threads); on a male aerator measure its outside diameter (it threads up inside the spout). Look at your old one — that tells you which.

Most hardware-store aerator kits include adapters for multiple sizes, and a dual-thread aerator fits both male and female spouts — when you genuinely can’t tell which gender you have, that’s the safe buy, and it’s the same price.

This is the step most “how to replace a faucet aerator” guides skip. Before screwing the aerator back on, run the water for 10–15 seconds with the aerator off. This flushes any debris loosened during cleaning out of the supply line and the faucet body — debris that would otherwise lodge in the new aerator and undo your work. Pfister explicitly recommends this step in their troubleshooting docs.

If you cleaned and reassembled the old aerator rather than buying new, stack the parts in the right order before threading it on: the mesh screen sits at the bottom (facing down toward the water exit), the flow restrictor above it, and the rubber gasket on top against the spout. A screen installed upside down can whistle or spray oddly. Then thread the new (or cleaned) aerator back on by hand. Counterclockwise to remove, clockwise to install. Hand-tight plus about a 1/8 turn is the right level of tightness — enough to seal the gasket, not enough to strip the threads or split the spout. Over-torquing with pliers is the most common way a successful aerator replacement turns into a cracked-housing replacement.

Turn the faucet on. The flow should be substantially better, and the spray pattern should be even and forceful instead of weak or sputtering.